It’s their first real display of emotion during a recent meeting in a hotel room overlooking Central Park, where they’ve come to discuss their new film, “Zero Dark Thirty.” The film, which depicts the CIA’s quest to find Osama bin Laden in the months leading up to his capture, opened Friday.

The pair previously teamed up for “The Hurt Locker,” which won the Academy Award for best picture in 2010. That film explored the emotional and physical toll exacted on a bomb disposal team during the Iraq war. The laughter on this early winter afternoon is precipitated by talk of what they might work on next.

“It’s a romantic comedy,” says screenwriter Boal, smiling and triggering a deep and prolonged laugh from Bigelow, his favorite director.

The two began their collaboration in 2005, when Bigelow read an article Boal had written for Playboy magazine, titled “The Man in the Bomb Suit,” which he wrote after being embedded with troops and bomb squads in Iraq. The story became the inspiration for “The Hurt Locker.”

Bigelow, 61, and Boal, 39, are widely rumored to be romantically involved, although they refuse to discuss it publicly. Bigelow was married to director James Cameron for two years and beat him out for the 2010 Oscar.

Clearly buoyed by Bigelow’s reaction to his words, Boal continues describing the plot of their next potential film. “It features the complicated relationship between a media-savvy general and his biographer,” he says, referring to the scandal that led General David Petraeus to resign as head of the CIA.

But, after considering the idea, Boal concludes it may not be that outrageous after all. “Actually, I keep joking about it but, the more I think about it, the more it could work,” he says.

For now, he and Bigelow are laser-focused on their current film, which has received four Golden Globe nominations, including best picture and best director, and is being buzzed about as an Oscar favorite. The film has also won several “best film” honors from critics’ groups, including the New York Film Critics Circle, the Boston Society of Film Critics, and the National Board of Review. And whatever their next project turns out to be, if history is any indication, current events will provide the inspiration. Boal and Bigelow were in Tora Bora, in the early stages of working on a film about the failure to find bin Laden, when bin Laden was killed by Navy SEALs in Pakistan in May 2011.

Despite the fact that almost everyone on the planet would know how the movie ends, the pair say they were immediately sure the story had the makings of a thrilling movie.

Andrew Kelly/Reuters

“We certainly didn’t come to it with an agenda, and I think we just wanted to bring the audience to the center and show what it would be like to be on the ground for this kind of operation,” says writer Mark Boal of his latest collaboration with director Kathryn Bigelow.

“I didn’t see the ending as a challenge,” says Bigelow. “What was fascinating was the inherent drama, and looking at the manhunt through the eyes of the men and women who were on the ground in Pakistan and Afghanistan.”

“When people used to ask me about [the end] when we were in the development stage, I’d say, ‘Well, everyone knew how “Titanic” ended and that worked,’ ” adds Boal. “And, of course, by saying that, I was giving the impression that there was a love story at the center of [‘Zero Dark Thirty’].”

Adding romance to the story to make it more appealing was not an option for these filmmakers. The story stays true to the information that Boal, a veteran journalist, reported about the manhunt. In fact, the project stirred some controversy last year when US Representative Peter King, chairman of the Congressional Homeland Security Committee, claimed that classified information had been leaked to the filmmakers.

Boal says he relied on his reporting skills as he would for any other journalistic project but would not get into the specifics of whom he met with because “that gets into the zone of source protection.”

He and Bigelow say every character in “Zero Dark Thirty” is based on a real person, although the names have been changed. (The film title refers to the military term for 30 minutes past midnight, which was the time Navy SEALs first set foot in bin Laden’s compound.)

The film is told from the perspective of Maya (Jessica Chastain), a young CIA officer, whose job is finding terrorists. After arriving in Pakistan, she immediately witnesses a horrifying interrogation scene involving waterboarding. Maya’s reaction goes from revulsion to steely determination, which is meant to echo the evolution of the nation’s conflicted attitude toward the response to terrorism, the filmmakers say.

Jason Clarke, who plays Dan, the agent who leads the torture interrogation, says the role gave him a new perspective on the toll the war has taken on people charged with fighting it.

“They say don’t judge a man until you’ve walked a mile in his shoes — well I haven’t walked nearly a mile in this guy’s shoes,” says Clarke. “Those scenes show us what happens to Dan. It’s not about judging him. It’s about showing what people do because we ask them to do it. It’s very well [to take a stand against torture], but it’s another to be in that position.”

Clarke adds that he knew his character’s humanity would be apparent, despite his inhumane actions, because Bigelow “loves her characters, no matter what they’re doing.”

“Mark and Kathryn have chosen to tell the story from the perspective of the people who were there,” he says. “The material hasn’t gotten out there, and this gets it out in a way that print and radio and news flashes can’t hope to do.”

Boal is adamant that the film neither justifies nor vilifies the actions of the CIA interrogators.

“We certainly didn’t come to it with an agenda, and I think we just wanted to bring the audience to the center and show what it would be like to be on the ground for this kind of operation,” he explains. “I’m wary of the word ‘message,’ but if there was a takeaway from the film, it’s that these people who work behind the scenes deserve some credit and it’s worthwhile to think about them too.”

Boal and Bigelow say they included the torture scenes because softening them or avoiding them altogether would be dishonest. Like the graphic bombing scenes in “The Hurt Locker,” Bigelow says the torture scenes in this film were necessary for the plot.

Jonathan Olley/Columbia Pictures

Navy SEALs raid Osama Bin Laden’s compound in “Zero Dark Thirty.”

“It’s not a fascination with war and darkness. It’s more of a fascination with events and the kind of journalistic approach to filmmaking,” she says. “The stories are unfolding, and an imagistic living history is being created. It’s controversial, but it’s also on the record as part of our history, and, again, we wanted to be faithful to the research and personal accounts.”

Bigelow quickly adds that the CIA agents used other tactics for information gathering, including “ground surveillance, track and trace surveillance, and good old-fashioned boots-on-the-ground sleuthing,” all of which were represented in the film.

In fact, a key piece of information was gleaned from tracking the cellphone of one of bin Laden’s close subordinates. When it was pointed out to Boal and Bigelow that the terrorists might have learned a thing or two from watching “The Wire,” the HBO series about Baltimore police who tap the phones of drug dealers in order to catch them, the filmmakers balked.

“It’s true that tracking phones is a tactic known to drug dealers, terrorists, and probably teenagers,” Boal says. “Maybe they don’t get HBO on Al Jazeera.”